The output distribution is altered - it starts responding "yes" 20% of the time - and then, conditional on that is more or less steered by the "concept" vector?
It doesn't matter if it's 'altered' if the alteration doesn't point to the concept in question. It doesn't start spitting out content that will allow you to deduce the concept from the output alone. That's all that matters.
I think this technique is going to be valuable for controlling the output distribution, but I don't find their "introspection" framing helpful to understanding.